The plan was outlined in prepared remarks to be delivered later on Wednesday by Li Jiaxiang, head of the Civil Aviation Administration of China, at an aviation forum in Beijing. The remarks did not specify details about the projects.

The announcement comes amid a wider effort by Beijing to increase overall infrastructure spending after economic growth slowed to a six-year low in the first quarter. The country's state planner has so far in the first six months approved billions of dollars of railway and airport projects.

He added that Chinese airlines now fly 553 routes to 127 cities in 51 nations, and plan to add 83 more routes over the summer and autumn period.

Government planners estimate China's airports will increase to 240 by 2020 from around 200 today.

Of the 500 billion yuan investment, 200 billion yuan will be spent on 51 projects in Chinese cities such as Urumqi and Kunming which are along routes marked out in China's "One Belt, One Road" initiative, Li said.

Chinese President Xi Jinping launched in 2013 an initiative to increase trade and extend China's influence with Central, West and South Asia as well as Europe and Africa through a series of projects ranging from oil and gas pipelines to railways.

In line with the strategy, Li also said that the government plans to expand China's traffic rights with Central, East and West Asian countries "at an appropriate time" which would pave the way for new routes.

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